Sustainable Shipping: More Conversion, Less CO2
Sustainable shipping doesn't have to be a trade-off. Most retailers think green = more expensive (bicycle couriers, CO₂ offsetting) or slower (no more same-day). That's true if you see sustainability as an extra service on top of your existing process. But done smartly, sustainable shipping actually lowers your costs. How? By letting customers choose a delivery day in the checkout, you spread orders across the week. The Monday peak in your warehouse flattens: fewer temp workers needed, up to 30% lower fulfilment costs. The carrier has a lower Tuesday peak: fuller vans, 20% fewer delivery vans on the road (University of Groningen research). And the customer? They appreciate the choice and convert 30% better.
Neleman, a Wuunder customer, saw exactly this: +30% conversion after activating GreenChoice in their checkout. At Soxs.co, 88% of customers voluntarily chose the green delivery day. Not because they had to, but because it was offered as an option. The result: higher conversion, lower fulfilment costs and less CO₂.
This page shows how to make your shipping more sustainable while lowering your costs.
Why sustainable shipping matters
The transport sector is responsible for a large share of CO₂ emissions. The growth of e-commerce means more and more parcels on the road. At Wuunder, we believe this can be different. Must be different.
Consumer data:
- 68% of consumers want to change their delivery day to help the environment (Wuunder/Panelwizard)
- 58% of consumers are willing to wait to help the environment (Wuunder/Panelwizard)
- 88% of consumers think it is important to have a choice of delivery day (Wuunder/Panelwizard)
- 68% of consumers support a green delivery day (Wuunder/Panelwizard)
- 45% of consumers believe there are not enough green options (Wuunder/Panelwizard)
- 38% of orders are placed during the weekend (Wuunder data)
Regulation:
Best Day Delivery with GreenChoice: the customer chooses, you save
It starts with a simple choice in the checkout: the customer picks a delivery day. Not necessarily the fastest, but the day that suits them best. GreenChoice helps customers make that choice: 88% voluntarily pick a later delivery day when GreenChoice is offered.
What this means for you as a retailer:
The Monday peak in your warehouse drops because orders are spread across the week. Fewer temp workers needed on Monday = lower fulfilment costs. The carrier has a lower Tuesday peak and can also save. Fuller vans, fewer trips, and the customer is home on the day they chose themselves: fewer failed deliveries.
The chain effect of one choice in the checkout:
- Customer picks delivery day → 88% consciously choose a later day
- Warehouse → orders spread across the week, Monday peak flattens, fewer temp workers
- Carrier → Tuesday peak flattens, fuller vans, fewer trips
- Environment → -7.5% CO₂ per shipment, 20% fewer delivery vans on the road
- Conversion → +30% higher conversion because customers appreciate the choice
GreenChoice is not a carbon offset programme (planting trees). It's actual reduction of transport movements. By smartly bundling deliveries per postcode and delivery day, carriers can deliver more parcels in a single trip.
GreenChoice is available for Shopware, Magento, Salesforce Commerce Cloud and via the Wuunder API. Is your webshop platform not listed? Contact our team and we'll look into adding your platform to the roadmap.
Proven results:
| Metric | Resultaat | Bron |
|---|---|---|
| Conversion uplift | +30% | University of Groningen, Neleman |
| CO₂ reduction | -7,5% | University of Groningen |
| Customers choosing green | 88% | University of Groningen, Soxs.co |
| Fewer delivery vans on the road | 20% | University of Groningen |
| Warehouse peak reduction | Tot 30% | Wuunder data |
Scientifically researched by the University of Groningen in collaboration with Wuunder. Read the full research
From checkout to warehouse: why sustainability lowers your costs
The effect of GreenChoice starts in the checkout and ripples through to your warehouse and carrier network. This is the chain most retailers overlook:
The Monday peak cycle (without GreenChoice):
Most B2C orders come in during the weekend. Monday is therefore the busiest packing day in your warehouse. Tuesday is the busiest delivery day for the carrier, and the day with the most delays. The result: you need extra temp workers on Monday, the carrier has overloaded vans on Tuesday, and the customer gets a rushed driver who doesn't have time to complete the delivery.
With GreenChoice:
By letting customers choose a delivery day in the checkout (other than the fastest), you spread orders across the week. The effect ripples through the entire chain:
- Warehouse: the Monday peak flattens. Fewer temp workers needed = up to 30% lower fulfilment costs
- Carrier: the Tuesday peak flattens. Fuller vans, fewer trips = 20% fewer delivery vans on the road and fewer delays
- Customer: consciously chooses a day they're home = fewer failed deliveries, fewer returns
- Environment: fewer trips + fuller vans = 7.5% less CO₂ per shipment
- Conversion: customers appreciate the choice = +30% higher conversion
One decision in the checkout, structurally lower costs across four links in the chain. That's why sustainability isn't a cost but a business model.
GreenChoice + bicycle couriers: even greener if you want
GreenChoice works with any carrier: the results above (7.5% less CO₂, 20% fewer delivery vans) are purely with regular carriers, no bicycle couriers needed. Want to go even further? You can combine GreenChoice with a bicycle courier.
Bicycle couriers are zero-emission, quiet and fast in urban areas. The challenge is that no single bicycle courier covers all of the Netherlands, Belgium or Germany. You need a different courier per postcode area, and the transfer costs to get shipments to the local hub make it more expensive per shipment than a regular carrier.
Wuunder Checkout can show a different carrier per postcode area, including bicycle couriers. The real win comes from first bundling via GreenChoice (more volume per delivery day per postcode) and then having the bundled shipments delivered by a bicycle courier. More volume per trip = lower transfer costs per shipment.
5 ways to make your shipping more sustainable
1. Offer a sustainable delivery option
GreenChoice in your checkout lets customers choose a delivery day that fits existing routes. No extra cost, less CO₂. By spreading orders, you eliminate Monday peaks and save on staffing.
2. Optimise your packaging
PuzzlPack calculates all possible shipment combinations per order and selects the packing method with the lowest transport price. Less material = less weight = less CO₂ in transport. Plus: you comply faster with EU PPWR requirements for less packaging waste.
3. Choose the right carrier per shipment
Not every shipment needs express (air freight). Standard road transport within the EU is up to 10x less CO₂-intensive than air freight. Wuunder automatically compares based on destination, dimensions, weight and delivery type. More about all cost components: shipping cost comparison.
4. Spread your orders
Peaks in your warehouse mean peaks in transport. Order spreading via the checkout flattens peaks: fewer temp workers, fuller vans, lower CO₂ per parcel. Up to 30% lower fulfilment costs.
5. Minimise returns
Every return doubles the CO₂ impact. Better product photos, size charts and Wuunder Returns with an exchange option (instead of return) lower your return rate and your footprint. More on international returns.
Wuunder PuzzlPack: less air, more content
A major problem in logistics is wasted space. Oversized boxes with lots of filler material mean fewer parcels fit in a delivery van, leading to more trips.
PuzzlPack analyses all possible shipment combinations per order: items together in one box, separately in multiple boxes, or as a pallet. For each combination, the all-in shipping price is calculated. Then the cheapest solution is automatically selected.
The result: less packaging material, fewer volumetric weight surcharges, less CO₂ per parcel, and lower shipping costs.
"Transport costs dropped by 20 to 30 percent."
Jan van Amerongen, Summertoys
Summertoys uses PuzzlPack to pack orders more efficiently. The result: less air shipped, 20 to 30% lower transport costs and fewer surcharges.
Want to know more about a greener shipping process?
We're happy to help you make your checkout and shipping greener!
What actually works in the checkout?
Wuunder and the University of Groningen tracked real choice behaviour in the live checkout of SOXS.co for eight months. The outcome is counter-intuitive: what webshops spend the most on (discounts and labels) works the least.
| Intervention | Share choosing sustainable |
|---|---|
| Default: fast delivery preselected | 7% |
| Adding a sustainability label | 10% |
| €0.50 shipping discount | 15% |
| €1.00 shipping discount | 20% |
| Preselecting the sustainable option | 75% |
| Preselection + discount + label | ~90% |
Giving away a euro gets you to 20%. Preselecting that same option gets you to 75%, and costs nothing.
The market is doing the opposite
Of 100 webshops analysed, 38% offer no sustainable delivery option at all. Of the 62 that do, 51.6% rely on discounts and 25.8% on information. Only 8 have the sustainable option preselected. The intervention with the biggest effect is the one least used.
Jeroen Gehlen, founder of Wuunder: "We see how much money leaks away in the checkout every day. Webshops invest in discounts and green labels because it feels logical, but this research shows something different. Preselecting the sustainable option changes the behaviour of many customers without costing a cent."
You set up preselection in Wuunder Checkout with GreenChoice. Platform not listed? Get in touch and we'll look at the options.
Emerce TV, November 2025: Jeroen Gehlen on Best Day Delivery (in Dutch) (From next day to best day: how sustainable delivery pays off)
The role of webshops
Research shows that 41% of consumers feel there is too much focus on speed in delivery. A sustainable mindset exists among consumers, but available choices are often lacking.
Webshops need to make sustainable options more visible, attractive and easy. By offering green delivery options as standard in the checkout, without extra cost and with clear explanation of the impact, you can make the difference together.
Wuunder and B Corp
Wuunder has been B Corp™ certified since June 2026. This means we meet the highest standards for social and environmental performance, transparency and accountability. B Corp is not a marketing label but an independent certification reassessed every 3 years.
What this means in practice:
- GreenChoice as a core product, not an afterthought
- PuzzlPack to reduce packaging waste
- CO₂ impact per shipment visible in the platform
- Transparent about our own footprint
Operational benefits summarised
The chain checkout→ warehouse→ carrier→ customer delivers concrete savings:
| Saving | Result | How |
|---|---|---|
| Fulfilment costs | Up to 30% lower | Order spreading via GreenChoice flattens the Monday peak, fewer temp workers needed |
| Warehouse process | 40% faster | Automated carrier selection and label generation via Wuunder Ship |
| Delivery vans on the road | 20% fewer (RUG) | Fuller vans through order spreading and route consolidation |
| CO₂ emissions | 7.5% lower (RUG) | Smart bundling via GreenChoice, fewer empty runs |
| Transport costs (PuzzlPack) | 20–30% lower | Packaging optimisation via PuzzlPack |
| Support queries | 70% fewer | Proactive track & trace communication, customer knows where parcel is |
Frequently asked questions
Q: Does sustainable shipping cost more?
A: No. GreenChoice doesn't cost more than standard delivery. The customer chooses a delivery day that fits existing routes, which is often even cheaper. So ask your carrier for a discount!
Q: Do customers actually choose the green option?
A: Yes. At Soxs.co, 88% of customers voluntarily chose the GreenChoice option. It's about offering the choice and clearly communicating the benefits and impact.
Q: What's the difference between carbon offsetting and carbon reduction?
A: Offsetting (planting trees) neutralises emissions after the fact. GreenChoice actually reduces emissions through smarter route planning and order spreading. Reduction is always better than offsetting.
Q: Does PuzzlPack also help with sustainability?
A: Yes. PuzzlPack calculates all shipment combinations per order and selects the option with the least volume and weight. Less material, less CO₂ in transport. And you pay fewer volumetric weight surcharges.
Q: Is Wuunder B Corp certified?
A: Yes, since June 2026. B Corp is an independent certification for companies meeting the highest standards for social and environmental performance.
- Emerce: Consument kiest duurzame bezorging vooral als de webshop dat al heeft voorgeselecteerd
- CustomerFirst: Voorselectie stimuleert duurzame bezorging
- Textilia: Standaard groen bezorgen in checkout verhoogt verantwoorde keuze tot 75%
- Fonk Magazine: Webshops that preselect the sustainable delivery option see sustainable deliveries rise sharply (in Dutch)